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                                                      992
           APPENDIX C                                                         Implementation Limits



           limits, applications producing PDF files are strongly advised to remain within
           them. Note, however, that memory limits are often exceeded before architectural
           limits (such as the limit on the number of indirect objects) are reached.

                                        TABLE C.1 Architectural limits
QUANTITY                LIMIT                  DESCRIPTION

integer                 2,147,483,647          Largest integer value; equal to 231 − 1.

                        -2,147,483,648         Smallest integer value; equal to −231.

real                     ± 3.403 × 1038        Largest and smallest real values (approximate).

                         ± 1.175 × 10   38     Nonzero real values closest to 0 (approximate). Values closer
                                               than these are automatically converted to 0.

                        5                    Number of significant decimal digits of precision in fractional
                                             part (approximate).
                        Note: To represent real numbers, Acrobat 6 uses IEEE single-precision floating-point
                        numbers, as described in the IEEE Standard for Binary Floating-Point Arithmetic (see
                        the Bibliography). Previous versions used 32-bit fixed-point numbers (16 bits on either
                        side of the radix point), which have greater precision but a much smaller range than
                        IEEE floating-point numbers. (Acrobat 6 still converts floating-point numbers to fixed
                        point for some components, such as screen display and fonts.)

string (in content      32,767                 Maximum length of a string, in bytes.
stream)
                                               Note: This restriction applies only to strings in content streams.
                                               There is no effective restriction on other strings in PDF files.

name                    127                    Maximum length of a name, in bytes.

indirect object         8,388,607              Maximum number of indirect objects in a PDF file.

q/Q nesting             28                     Maximum depth of graphics state nesting by q and Q operators.
                                               (This is not a limit of Acrobat as such, but arises from the fact
                                               that q and Q are implemented by the PostScript gsave and gre-
                                               store operators when generating PostScript output; see imple-
                                               mentation note 176 in Appendix H.)

DeviceN components      32                     Maximum number of colorants or tint components in a DeviceN
                                               color space.

CID                     65,535                 Maximum value of a CID (character identifier).

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